Process for the control of bacteria in water flooding operations



PROCESS FOR THE CONTROL OF BACTERIA 1N WATER FLOODING OPERATIONS Edward 0. Bennett, Houston, Tex., and Edward B.

Hodge, Terre Haute, Ind., assignors to Commercial Solvents Corporation, New York, N.Y., a corporation of Maryland No Drawing. Filed May 13, 1959, Ser. No. 812,822 2 Claims. (Cl. 252-855) Our invention relates to the control of sulfate reducing bacteria in water flooding operations used in the secondary recovery of petroleum oils, and more particularly, to controlling such organisms by incorporating into the flooding water effective amounts of Z-nitrobutyl succinate.

US. Patent 2,839,467 lists many of the problems found in the secondary oil recovery art and the means whereby some of these problems have been solved. The problem of controlling sulfate reducing bacteria is ever present and always difiicult, as the growth of the microorganisms is not controlled by economically practicable amounts of many bactericides generally utilized in bacterial control and the microorganisms sometimes becomes resistant to generally used bactericides.

We have now discovered that sulfate reducing microorganisms are economically controlled by the addition of 2-nitrobutyl succinate to the flooding water.

The usual procedure for the treatment of water to be utilized in flooding operations is to produce a concentrate of the bactericide in water and then continuously injected this concentrate into the water to be used in flooding operations at a rate which forms the desired dilution of the bactericide. This is done prior to pumping the water into the oil-bearing subterranean formation. Sampling and checking of the water for sulfate reducing bacteria will show whether the chemical concentration needs to be raised or may be lowered to efiect an elimination of sulfate reducing bacteria from the water.

Alternately, the 2-nitrobutyl succinate utilized in our process may be added to the oil-bearing formations periodically, for example, once a week, as a high potency concentrate or the undiluted 2-nitrobutyl succinate may be injected into the formation.

We have found that 2-nitrobutyl succinate is active against some strains of sulfate reducing bacteria in water at concentrations as low as 2-5 p.p.m. However, we prefer to utilize concentrations in excess of 2-5 p.p.m.

ttes Patent Patented Sept. 26, 1961 Example I In a water treatment plant, a water concentrate containingZ-nitrobutyl succinate is continuously added to water to be pumped into subterranean oil-bearing formations at such a rate that a 250 p.p.m. solution of 2-nitrobutyl succinate is formed. The Z-nitrobutyl succinate flooding water is pumped into the oil-bearing formation I and is completely effective in preventing bacterial plugging of the oil-bearing sands and the piping system utilized in the water flooding operations.

Now having described our invention, what we claim is:

1. In the process of secondary oil recovery characterized by the step of injecting flooding water into oilbearing subterranean formations to displace portions of the residual oil therein, the improvement which comprises adding to said injected flooding water in excess of about 2-5 p.p.m. of bis(2-nitrobutyl)succinate to inhibit the growth of sulfate reducing bacteria within said formations.

2. In a flooding process for the recovery of oil from oil-bearing subterranean formations, the improvement which comprises flooding the oil-bearing formations with an aqueous liquid containing in excess of 2-250 p.p.m. of bis(2-nitrobutyl)succinate.

References Cited in the file of this patent UNITED STATES PATENTS 1,873,732 Adams Aug. 23, 1932 2,368,765 Lawrence Feb. 6, 1945 2,692,231 Stayner et a1. Apr. 15, 1947 2,839,467 Hutchinson et al June 17, 1958 2,917,428 Hitzman Dec. 15, 1959 FOREIGN PATENTS' 664,339 Great Britain Jan. 2, 1952 107,419 Australia May 25, 1939 

1. IN THE PROCESS OF SECONDARY OIL RECOVERY CHARACTERIZED BY THE STEP OF INJECTING FLOODING WATER INTO OILBEARING SUBTERRANEAN FORMATIONS TO DISPLACE PORTIONS OF THE RESIDUAL OIL THEREIN, THE IMPROVEMENT WHICH COMPRISES ADDING TO SAID INJECTED FLOODING WATER IN EXCESS OF ABOUT 2-5 P.P.M. OF BIS(2-NITROBUTYL) SUCCINATE TO INHIBIT THE GROWTH OF SULFATE REDUCING BACTERIA WITHIN SAID FORMATIONS. 